What is MVHR?

Mechanical Ventilation Heat Recovery (MVHR) systems provide fresh clean filtered air constantly at a balanced rate, running 24 hours a day, 7 days a week, 365 days a year. Heat recovery is a balanced whole house ventilation system that both supplies and extracts air and recovers up to 90% of heat that would have otherwise been lost through the ventilation process; proving, that alongside a heat pump, you can get the maximum efficiency for your home.

When installing an Mechanical Ventilation Heat Recovery system it is important to understand Building Regulations & Design Considerations as there are certain regulations you need to go by. Please see below for more information on this.

How does MVHR work?

Mechanical Ventilation Heat Recovery systems work by extracting the stale air and moisture out of wet rooms (kitchens, bathrooms, etc.) on a continual basis. A heat exchanger extracts the heat from waste air first. At the same time, fresh air from outside is taken in and filtered. The clean fresh air is then supplied to living areas around the house (lounge, bedrooms, etc). This ensures the air inside the house is not only healthier for the occupants (great for any allergy sufferers!), but also the building as well (no condensation, damp or mould).

Types of MVHR

Ice Energy provides you with 2 types of MVHR systems; Rotary and Counterflow. Both of these systems have their own perks and benefits, but each of them provide high efficiency levels for your home and are around 80-90% efficient, recovering lost heat and keeping a constant flow of fresh clean air.


Rotary heat exchangers work by pulling damp air through a rotating drum of aluminium plates to transfer heat, and then pushing clean filtered air out. These MVHR systems have an efficiency rating of up to 86%.


Counterflow heat exchangers are slightly more efficient than that of a Rotary MVHR system as they have an efficiency rating of up to 90%. Counterflow MVHR systems work by having air pass in opposite directions, separated by a plate to transfer heat.

Building Regulations & Design Considerations

Those wishing to build or carry out renovations today are faced with a challenge. The current building regulations demand better insulated and air-tight buildings in order to protect our resources and the environment. Air-tight and well insulated buildings prevent natural ventilation through the building's component parts, which could result in the formation of mould through damp stagnant stale air. This is detrimental to both the building structure and the health of the occupants.

Standard Assessment Procedure (SAP)

Mechanical Ventilation Heat Recovery can be installed in any new build dwelling, as well as refurbished buildings.  To maximise the Heat Recovery System performance, especially the heat exchange efficiency, it is best suited for dwellings with an air tightness level of 5 (measured at m3/hr/m2 at 50 Pa). Please note: Part F of the 2010 Building Regulations recommend an MVHR system is installed in homes with an air tightness value of 5 or less. Effectively, the more sealed the dwelling, the more effective the heat recovery system will be for the home and its occupants. If the building is leaky to begin with, the rewards of recovering the heat are minimised and somewhat lost.

MVHR Installation at Sena House